What's your favorite note-taking/productivity tool and why?

I'm doing some research about what you like the most about whatever note-taking/productivity tool that you can't live without. For my side, I love the simplicity and easy-setup about the tables that Notion offers, to quickly organize my finances, I definitely can't live without it. 🤔 What about you? Also, is there any improvement that you would like to see regarding your picking?